Polyamide hot-melt resin granules loaded with active ingredients

ABSTRACT

The present document describes a polyamide hot-melt resin having a chemical structure consisting of dimerized fatty acids and diamines, loaded with an active ingredient. The dimerized fatty acids may have 12 to 24 carbons and the diamines may have 2 to 14 carbons. The amine residual functional groups and acid residual functional groups within the polyamide hot-melt resin may have a [NH 2 ]/[COOH] molar ratio below 5, and the active ingredient may be incorporated in quantities of between about 0.01 and about 55% by weight of weight of the resin. The present document also describes items molded from the polyamide hot-melt resins, and processes of preparing the polyamide hot-melt resins.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under of U.S. provisional patentapplication No. 62/608,994 filed on Dec. 21, 2017, the specification ofwhich is hereby incorporated by reference in its entirety.

BACKGROUND (a) Field

The present invention relates to the field of solid polymer materialincorporating a liquid solution of active ingredient. Specifically, thepresent invention relates to a plurality of polyamide hot-melt resingranules containing an active ingredient.

(b) Related Prior Art

The use of polyamide hot-melt adhesive resins is known, either directlyas glue or as one of the constituents of adhesive compositions. In suchcompositions, they are mixed with other polymers, specificallypolyolefin such as copolymers of ethylene and vinyl acetate, acrylics,styrenics, polyurethanes. For example, US patent application publicationNo. US2015/0073093 describes the use of a particular grade of polyamidehot-melt resins as a constituent of a composite polymer with greatadhesive strength. The chemical properties of the different constituentsof an adhesive composition determine the nature of the differentmaterials (e.g. metals, plastics, papers, etc.) to which it adheres.

The use of polyamide hot-melt adhesive resins as a gelling agent is alsoknown. Indeed, European patent EP1027032 describes the use of apolyamide hot-melt resin in a gel containing limonene intended for airpurification. This specific category of polyamide resin is also used incompositions of paint or ink (see US patent application No.US2005/134664).

In other compositions, such as in French patent No. FR2233380, it isdisclosed polymer supports of a thermoplastic polyamide type loaded witha volatile active ingredient to combat arthropod pests. In French patentNo. FR2941972, microparticles of thermoplastic polyamides (PA) of thefamily of PA6, PA11, PA12, etc., loaded with active ingredient areproposed. But the above-mentioned thermoplastic polyamides arefundamentally different as regards their chemical structure compared topolyamide hot-melt resins on which are based the invention.

In the above-mentioned polyamide hot-melt resins, not all are capable ofserving satisfactorily as a support for the incorporation of alipophilic solution containing at least one active ingredient insignificant quantity.

The polyamide hot-melt resins that are suitable for the desired aimcontain amine and/or carboxyl type residual functional groups. They canbe obtained in different ways, specifically by polycondensationreactions between acids and amines.

It has been observed that a certain category of polyamide resinsbelonging to the family of hot-melt adhesive resins can serve as a solidsupport capable of incorporating a lipophilic solution of activeingredient in significant quantity. Moreover, these polyamide hot-meltadhesive resins, once loaded with active ingredient, have the additionaladvantage of being capable of being shaped by common plastics processingtechniques namely, specifically, injection molding, extrusion,hot-pressing and coating in order to obtain items loaded with activeingredient.

Furthermore, it has been observed that many polyamide hot-melt resinshave a liquid incorporation capacity below 10% by weight and to a lesserdegree below 15% by weight. Now, it is advantageous to be able toincorporate a quantity of liquid exceeding 20% by weight of the polymerso as to have control of the dose of diffused active ingredient, theduration of diffusion and to limit any risks of sequestration of certainactive ingredients that can be found in this family of polymers.

A need therefore exists to provide polyamide hot-melt resin granulescapable, of incorporating a significant quantity of active ingredientsolution.

Furthermore, a need exists to provide polyamide hot-melt resin granulesthus loaded with active ingredient that may be shaped to obtain itemsthat also contain the active ingredient.

In the present invention, the inventors have identified a category ofpolyamide hot-melt resins that suitable for use as a support for theincorporation of active ingredient in liquid form and that may be formedinto useful items.

SUMMARY

According to an embodiment, there is provide a polyamide hot-melt resinhaving a chemical structure consisting of dimerized fatty acids anddiamines, the polyamide hot-melt resin being loaded with an activeingredient, wherein the dimerized fatty acids have 12 to 24 carbons andthe diamines have 2 to 14 carbons, wherein amine residual functionalgroups and acid residual functional groups within the polyamide hot-meltresin have a [NH₂]/[COOH] molar ratio below 5, and wherein the polyamidehot-melt resin incorporates an active ingredient in quantities ofbetween about 0.01 and about 55% by weight of weight of the resin.

The polyamide hot-melt resins may incorporate an active ingredient inquantities of between about 1 and about 50, or about 5 and about 50%, orabout 10 and about 45%, or about 15 and about 45%, or about 20 and about45% by weight of weight of the resin.

The [NH₂]/[COOH] molar ratio of the residual functional groups may bebelow 2.

The [NH₂]/[COOH] molar ratio of the residual functional groups may bebelow 1.

The acid residual functional group content of the polyamide hot-meltresins may exceed 2 mg of KOH/g of resin granules.

The amine residual functional group content of the polyamide hot-meltresins may be below 5 mg of KOH/g of resin granules.

The softening temperature of the resins may be between about 145 andabout 200° C.

The softening temperature of the resins may be between about 150 andabout 190° C.

The dimerized acid may contain a monocarboxylic, a dicarboxylic or amulticarboxylic acid.

The dimerized acid may be obtained by a polymerization reaction betweenan unsaturated fatty acid, namely oleic acid, linoleic acid, a dry orsemi-dry fatty acid, and a monoalcohol ester with a low molecular weightderived from these fatty acids.

The diamines may be chosen from the group consisting of ethylenediamine,triethylenediamine, tetraethylenediamine, hexamethylenediamine, p- orm-xylenediamine, 4,4′-methylene bis(cyclohexylamine),2,2-bis(4-cyclohexylamine), polyetherdiamine, isophoronediamine, 1,2-,1,3-, 1,4-cyclohexanediamine, 1,4-bis(2′-aminoethyl)benzene, piperazine,1,3-di-4-piperidylpropane, and dimerized amines having amine functionsfrom the conversion of the carboxyl group of the above dimerized acids.

The active ingredient may be chosen from an insecticide, an insectrepellent, a microbicide, an attractant, a pheromone, a hormone, avitamin, a perfume, an essential oil, a drug, a plant extract, or amixture thereof.

The insecticide and the insect repellent are selected from the groupconsisting of pyrethroids, pyrethrines, carbamates, formamidines,carboxylic esters, N,N-diethyl-3-methylbenzamide (DEET),phenylpyrazoles, organophosphorus compounds, organohalogen compounds,neonicotinoids, avermectines, ivermectine, abamectine, doramectine,spinosyns, essential oils, terpenes, alcohol derivatives of terpenes,ester derivatives of terpenes, aldehyde derivatives of terpenes,sesquiterpenes, alcohol derivatives of sesquiterpenes, ester derivativesof sesquiterpenes, aldehyde derivatives of sesquiterpenes.

According to another embodiment, there is provide a molded item madefrom a plurality of polyamide hot-melt resin granules according to thepresent invention, the item having been molded by injection-molding,blow-molding, extrusion, hot-pressing or coating.

The acid residual functional group content of the polyamide hot-meltresins may exceed 2 mg of KOH/g of resin granules, and the amineresidual functional group content of the polyamide hot-melt resins maybe below 5 mg of KOH/g of resin granules.

The active ingredient may be chosen from an insecticide, an insectrepellent, a microbicide, an attractant, a pheromone, a hormone, avitamin, a perfume, an essential oil, a drug, a plant extract, or amixture thereof.

According to another embodiment, there is provide a molded item madefrom a plurality of polyamide hot-melt resin granules synthesized fromdimerized fatty acids having 12 to 24 carbons and diamines having 2 to14 carbons, the resins granules being loaded with active ingredient,wherein the polyamide hot-melt resin granules have amine residualfunctional groups and acid residual functional groups in a [NH₂]/[COOH]molar ratio below 5 and in a quantity of the active ingredient between0.01 and 55% by weight compared to the total weight of the molded item,the item having been molded by injection-molding, blow-molding,extrusion, hot-pressing or coating.

The acid residual functional group content of the polyamide hot-meltresins may exceed 2 mg of KOH/g of resin granules, and the amineresidual functional group content of the polyamide hot-melt resins maybe below 5 mg of KOH/g of resin granules.

The active ingredient may be chosen from an insecticide, an insectrepellent, a microbicide, an attractant, a pheromone, a hormone, avitamin, a perfume, an essential oil, a drug, a plant extract, or amixture thereof.

According to another embodiment, there is provide a method for obtainingpolyamide hot-melt resin granules loaded with active ingredient inliquid solution, and having a chemical structure consisting of dimerizedfatty acids having 12 to 24 carbons and diamines having 2 to 14 carbons,the method comprising the steps of:

-   -   a) heating a polyamide hot-melt resin granule consisting of        dimerized fatty acids having 12 et 24 carbons and diamines        having 2 to 14 carbons, having amine and acid residual        functional groups whose [NH₂]/[COOH] molar ratio may be below 5        and having a softening temperature of between 145 and 200° C.,        to between about 30 and about 95° C.;    -   b) mixing a liquid solution of the active ingredient onto the        polyamide hot-melt resin granules heated in step b), to obtain a        polyamide hot-melt resin granule loaded with active ingredient.

The [NH₂]/[COOH] molar ratio of the residual functional groups may bebelow 2.

The [NH₂]/[COOH] molar ratio of the residual functional groups may bebelow 1.

The acid residual functional group content of the resins granules mayexceed 2 mg of KOH/g of resin granules.

The amine residual functional group content of the resins granules maybe below 5 mg of KOH/g of resin granules.

The softening temperature of the resins may be between about 150 andabout 190° C.

The active ingredient may be chosen from an insecticide, an insectrepellent, a microbicide, an attractant, a pheromone, a hormone, avitamin, a perfume, an essential oil, a drug, a plant extract, or amixture thereof.

The insecticide and the insect repellent are selected from the groupconsisting of pyrethroids, pyrethrines, carbamates, formamidines,carboxylic esters, N,N-diethyl-3-methylbenzamide (DEET),phenylpyrazoles, organophosphorus compounds, organohalogen compounds,neonicotinoids, avermectines, ivermectine, abamectine, doramectinespinosyns, essential oils, terpenes, alcohol derivatives of terpenes,ester derivatives of terpenes, aldehyde derivatives of terpenes,sesquiterpenes, alcohol derivatives of sesquiterpenes, ester derivativesof sesquiterpenes, aldehyde derivatives of sesquiterpenes. According toanother embodiment, there is provide a use of the polyamide hot-meltresin granules according to the present invention as a solid supportincorporating between 0.01 and 55% by weight of a liquid solutioncontaining an active ingredient having biocide, well-being and cosmetic,therapeutic, and phytosanitary effects or a mixture thereof.

The following terms are defined below.

The term “active ingredient” is intended to mean, in the context of thepresent invention, one active molecule or a combination of activemolecules. The active ingredient can be in liquid form or in solid orviscous form but made liquid by solubilization, by heating or any otherknown means, depending on its chemical nature. Examples of activemolecules are provided below. In the context of the invention, theliquid solution of active ingredient means that the latter constitutesall of the liquid or that the active ingredient as defined above isformulated with solvents and/or formulation vectors.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present disclosure will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 illustrates the influence of the [NH₂/COOH] molar ratio ofresidual functional groups on the capacity of a polyamide hot-meltresins according to the present invention to incorporate liquid; and

FIG. 2 illustrates the influence of the softening temperature on thecapacity of polyamide hot-melt resins according to the present inventionto incorporate a liquid containing an active ingredient.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

The present invention is directed to polyamide hot-melt resins whosechemical structure consists of dimerized fatty acids and diamines,loaded with a liquid solution of active ingredient. In the context ofthe invention, the liquid solution of active ingredient means that thelatter constitutes all of the liquid or that the active ingredient asdefined above is formulated with solvents and/or formulation vectors.

In embodiments, there is disclosed polyamide hot-melt resins whosechemical structure consists of dimerized fatty acids and diamines. Inembodiments, the resins are loaded with an active ingredient, and thedimerized fatty acids have 12 to 24 carbons and the diamines have 2 to14 carbons, the amine and acid residual functional groups within theresins have a [NH₂]/[COOH] molar ratio below 5, and the resinsincorporate an active ingredient in quantities of between about 0.01 andabout 55%, or from about 0.1 and 55%, or from about 1 and 55%, or fromabout 5 and 55%, or from about 10 and 55%, or from about 15 and 55%, orfrom about 20 and 55%, or from about 25 and 55%, or from about 30 and55%, or from about 35 and 55%, or from about 40 and 55%, or from about45 and 55%, or from about 50 and 55%, or from about 0.01 and about 50%,or from about 0.1 and 50%, or from about 1 and 50%, or from about 5 and50%, or from about 10 and 50%, or from about 15 and 50%, or from about20 and 50%, or from about 25 and 50%, or from about 30 and 50%, or fromabout 35 and 50%, or from about 40 and 50%, or from about 45 and 50%, orfrom about 0.01 and about 45%, or from about 0.1 and 45%, or from about1 and 45%, or from about 5 and 45%, or from about 10 and 45%, or fromabout 15 and 45%, or from about 20 and 45%, or from about 25 and 45%, orfrom about 30 and 45%, or from about 35 and 45%, or from about 40 and45%, or from about 0.01 and about 40%, or from about 0.1 and 40%, orfrom about 1 and 40%, or from about 5 and 40%, or from about 10 and 40%,or from about 15 and 40%, or from about 20 and 40%, or from about 25 and40%, or from about 30 and 40%, or from about 35 and 40%, or from about0.01 and about 35%, or from about 0.1 and 35%, or from about 1 and 35%,or from about 5 and 35%, or from about 10 and 35%, or from about 15 and35%, or from about 20 and 35%, or from about 25 and 35%, or from about30 and 35%, or from about 0.01 and about 30%, or from about 0.1 and 30%,or from about 1 and 30%, or from about 5 and 30%, or from about 10 and30%, or from about 15 and 30%, or from about 20 and 30%, or from about25 and 30%, or from about 0.01 and about 25%, or from about 0.1 and 25%,or from about 1 and 25%, or from about 5 and 25%, or from about 10 and25%, or from about 15 and 25%, or from about 20 and 25%, or from about0.01 and about 20%, or from about 0.1 and 20%, or from about 1 and 20%,or from about 5 and 20%, or from about 10 and 20%, or from about 15 and20%, or from about 0.01 and about 15%, or from about 0.1 and 15%, orfrom about 1 and 15%, or from about 5 and 15%, or from about 10 and 15%,or from about 0.01 and about 10%, or from about 0.1 and 10%, or fromabout 1 and 10%, or from about 5 and 10%, or from about 0.01 and about5%, or from about 0.1 and 5%, or from about 1 and 5%, or from about 0.01and about 1%, or from about 0.1 and 1%, or from about 0.01 and about0.1%, or 0.01%, 0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%,50%, 55% by weight of their weight. Preferably, the resins incorporatean active ingredient in quantities of between about 1 and about 50%, orbetween about 5 and about 50%, or between about 10 and about 45%, orbetween about 15 and about 45%, or between about 20 and about 45% byweight.

According to a preferred embodiment, the [NH₂]/[COOH] molar ratio of theresidual functional groups of the resins is below 2, and most preferablybelow 1.

According to an embodiment, the acid residual functional group contentof the polyamide hot-melt resins exceeds 2 mg of KOH/g of resingranules.

According to another embodiment, the amine residual functional groupcontent of the polyamide hot-melt resins is less than 5 mg of KOH/g ofresin granules.

According to another embodiment, the softening temperature of thepolyamide hot-melt resins is between about 145 and about 200° C., orfrom about 150 and about 200° C., or from about 155 and about 200° C.,or from about 160 and about 200° C., or from about 165 and about 200°C., or from about 170 and about 200° C., or from about 175 and about200° C., or from about 180 and about 200° C., or from about 185 andabout 200° C., or from about 190 and about 200° C., or from about 195and about 200° C., or about 145 and about 195° C., or from about 150 andabout 195° C., or from about 155 and about 195° C., or from about 160and about 195° C., or from about 165 and about 195° C., or from about170 and about 195° C., or from about 175 and about 195° C., or fromabout 180 and about 195° C., or from about 185 and about 195° C., orfrom about 190 and about 195° C., or about 145 and about 190° C., orfrom about 150 and about 190° C., or from about 155 and about 190° C.,or from about 160 and about 190° C., or from about 165 and about 190°C., or from about 170 and about 190° C., or from about 175 and about190° C., or from about 180 and about 190° C., or from about 185 andabout 190° C., or about 145 and about 185° C., or from about 150 andabout 185° C., or from about 155 and about 185° C., or from about 160and about 185° C., or from about 165 and about 185° C., or from about170 and about 185° C., or from about 175 and about 185° C., or fromabout 180 and about 185° C., or about 145 and about 180° C., or fromabout 150 and about 180° C., or from about 155 and about 180° C., orfrom about 160 and about 180° C., or from about 165 and about 180° C.,or from about 170 and about 180° C., or from about 175 and about 180°C., or about 145 and about 175° C., or from about 150 and about 175° C.,or from about 155 and about 175° C., or from about 160 and about 175°C., or from about 165 and about 175° C., or from about 170 and about175° C., or about 145 and about 170° C., or from about 150 and about170° C., or from about 155 and about 170° C., or from about 160 andabout 170° C., or from about 165 and about 170° C., or about 145 andabout 165° C., or from about 150 and about 165° C., or from about 155and about 165° C., or from about 160 and about 165° C., or about 145 andabout 160° C., or from about 150 and about 160° C., or from about 155and about 160° C., or about 145 and about 155° C., or from about 150 andabout 155° C., or about 145 and about 150° C., or 145° C., 150° C., 155°C., 160° C., 165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195°C., 200° C., and preferably from about 150 to about 190° C.

In embodiments, to obtain the polyamide hot-melt resins suitable for thepresent invention requires a multi-step synthesis reaction whichinvolves a step of extraction of vegetable oils. Suitable oils includewithout limitations tall oil, soya oil, maize oil, rice bran oil andsunflower oil, from which unsaturated fatty acids are extracted bydifferent known methods such as extraction with organic solvents (e.g.hexane) which provides solid/liquid or liquid/liquid extraction,followed by distillation to remove residual solvent. This is followed bya dimerization step to obtain a complex mixture of diacids and, lastly,a polycondensation step with a mixture of diamines. Advantageously, theproduct obtained is a solid in the form of granules with an averageparticle size between about 2 and about 5 mm, or from about 2 to about 4mm, or from about 2 to about 3 mm, or from about 3 to about 5 mm, orfrom about 3 to about 4 mm, or from about 4 to about 5 mm. Therefore,the dimerized fatty acids are synthesized from unsaturated fatty acidsextracted from the vegetable oils.

In embodiments, the initial diacid and diamine content, the choice oftheir chemical nature, as well as the mono or polyacids (or amines)added at the time of polymerization will affect the physico-chemicalproperties of the polyamide hot-melt resins finally obtained.Specifically, the softening temperature can vary from 145 and about 200°C., preferably 150 to 190° C., as indicated above. By the nature of thesynthetic route used to synthesize the polyamide hot-melt resins,residual acidic functional groups, specifically carboxylic acids oramine exist within the granules obtained. In a known way, their contentcan be titrated and is expressed in mg of KOH per gram of polyamideresin granules.

The titration methods involve dissolving polyamide hot-melt resins inpropanol with the aid of reagents such as phenolphthalein orbromophenol. It is known that when resins have comparable amine andresidual acid function contents, they are broadly neutral. In all othercases, they are more or less acidic or basic depending on the quantityof one or the other of these two residual functional groups.

In embodiments, the acid component formed by C₁₂-C₂₄ dimerized acid maycontain a monocarboxylic, a dicarboxylic or a multi carboxylic acid. Thedimerized acid can be obtained by a polymerization reaction between anunsaturated fatty acid, such as oleic acid, linoleic acid, a dry orsemi-dry fatty acid, and a mono alcohol ester with a low molecularweight derived from these fatty acids. Occasionally, in order to reducethe degree of unsaturation of the dimerized acid, fatty acids can behydrogenated before or after fractionation.

According to an embodiment, the monocarboxylic acids may be chosen fromacetic acid, propionic acid, benzoic acid, lauric acid, oleic acid,stearic acid, tall oil fatty acid, cyclohexane carboxylic acid and1-adamantanecarboxylic acid. These acids can be used alone or incombination with each other. According to some embodiments, thesemonocarboxylic acids may be obtained specifically from plant extracts aswell as from black liquors produced by the paper industry.

According to an embodiment, the dicarboxylic acids may be chosen fromoxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,maleic acid, furamic acid, phthalic acid, terephthalic acid, 1,3- or1,4-cyclohexanedicarboxylic acid, 1,3-adamantanedicarboxylic acid,pimelic acid, suberic acid, azelaic acid, sebacic acid,nonamethylendicarboxylic acid, decamethylenedicarboxylic acid,undecamethylenedicarboxylic acid, dodecamethylenedicarboxylic acid,tridecamethylenedicarboxylic acid, tetradecamethylenedicarboxylic acid,pentadecametyledicarboxylic acid and hexadecamethylenedicarboxylic acid.These acids can be used alone or in combination.

The multicarboxylic acids are chosen from 1,2,4-benzenetricarboxylicacid, 2,5,7-naphthalenetricarboxylic acid,1,2,4-naphthalenetricarboxylic acid, 1,2,4-butan tricarboxylic acid,1,2,5-hexanetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid,tetra(methylenecarboxyl)methane acid, 1,2,7,8-octanetetracarboxylic acidand pyromellitic acid. These acids can be used alone or in combinationwith each other.

According to an embodiment, the diamines may be chosen from the groupconsisting of by ethylenediamine, triethylenediamine,tetraethylenediamine, hexamethylenediamine, p- or m-xylenediamine,4,4′-methylene bis(cyclohexylamine), 2,2-bis(4-cyclohexylamine),polyetherdiamine, isophoronediamine, 1,2- 1,3-, or1,4-cyclohexanediamine, 1,4-bis(2′-aminoethyl)benzene, piperazine,1,3-di-4-piperidylpropane, as well as dimerized amines having aminefunctions from the conversion of the carboxyl group of the abovedimerized acids. These diamines can be used alone or in combination witheach other.

According to another embodiment, the polyamide hot-melt resin granulesaccording to the present invention may therefore be obtained from acomplex mixture of dimerized fatty acids and polyamines.

In embodiments of the present invention, an active ingredient isincorporated with the granules. According to an embodiment, the activeingredient may be of natural origin or synthetic origin. According toanother embodiment, the active ingredient may have biocidal, well-being,cosmetic, therapeutic, phytosanitary effects or properties or a mixturethereof.

According to an embodiment, the active ingredient may be a biocidechosen from an insecticide, an insect repellent, a microbicide (abactericide, a fungicide, a virucide). According to another embodiment,the active ingredient may be selected from an attractant, a pheromone, ahormone, a vitamin, a perfume, an essential oil, a drug, a plant extractor a mixture thereof.

According to an embodiment, active ingredients with a cosmetic effect,pharmaceutical active ingredients and active ingredients with aphytosanitary effect can be formed by the combination of several activemolecules.

The insecticides and insect repellents according to the presentinvention may be in liquid, viscous, or solid form. They may bespecifically chosen from the group comprising pyrethroids [e.g.permethrine, deltamethrine, cypermethrine, tetramethrine), pyrethrinesand their derivatives, carbamates, formamidines (e.g. amitraz),carboxylic esters (e.g. IR3535), N,N-diethyl-3-methylbenzamide (DEET),phenylpyrazoles (e.g. Fipronil), organophosphorus compounds,organohalogen compounds, neonicotinoids, avermectines and theirderivatives, spinosyns, essential oils and their components (examples:terpenes and their derivatives (alcohols, esters, aldehydes) andsesquiterpenes and their derivatives (alcohols, esters, aldehydes)].

According to an embodiment, the active ingredient in liquid form may beincorporated as such, or it may be formulated with well-known vectorssuch as a vegetable oil, a mineral oil, a solvent, a surfactant, aplasticizer or a combination thereof. According to an embodiment, thevector may be chosen from the group of carbonates (e.g. propylenecarbonates, polypropylene carbonates, glycerin carbonates), esters (e.g.dimethyl isosorbide, dimethyl succinate, dimethylglutarate, dimethyladipate, diisobutyl succinate, diisobutylglutarate, diisobutyladipate,butylphtalate, diisodecylphtalate, dibutylephtalate,methylglycolphtalate, benzylbutylephtalate), ethers (e.g.ipropyleneglycolmethyl ether, propyleneglycol ether), fatty alcohols(e.g. glycerol and derivatives thereof, propylene glycol, polypropyleneglycol, polyethylene glycol, polypropylene oxide glycol), vegetableoils, mineral oils or a mixture thereof.

According to another embodiment, the liquid that comprises the activeingredient(s) can also contain formulation additives such as colorings,anti-UV agents (e.g. benzophenone, benzotriazole,tris(tetramethylhydroxypiperidinol)citrate, octisalate,ethylhexylsalicylate, butyl methoxydibenzoylmethane,diethylhexylsyringylidenemalonate, 2-hydroxy-4-methoxy-benzophenone),etc.

According to a second object of the present invention, there isdisclosed a method for obtaining a plurality of polyamide hot-melt resingranules that have a chemical structure consisting of dimerized fattyacids having 12 to 24 carbons and diamines having 2 to 14 carbons, thegranules being loaded with an active ingredient in liquid solution,wherein the method comprises the steps of:

-   -   a. heating a polyamide hot-melt resin granule consisting of        dimerized fatty acids having 12 et 24 carbons and diamines        having 2 to 14 carbons, having amine and acid residual        functional groups whose [NH₂]/[COOH] molar ratio is below 5 and        having a softening temperature of between 145 and 200° C., to        between about 30 and about 95° C.;    -   b. mixing a liquid solution of the active ingredient onto the        polyamide hot-melt resin granule heated in step b), to obtain a        polyamide hot-melt resin granule loaded with active ingredient.

According to embodiments, the softening temperature of the polyamidehot-melt resins is between about 145 and about 200° C., or from about150 and about 200° C., or from about 155 and about 200° C., or fromabout 160 and about 200° C., or from about 165 and about 200° C., orfrom about 170 and about 200° C., or from about 175 and about 200° C.,or from about 180 and about 200° C., or from about 185 and about 200°C., or from about 190 and about 200° C., or from about 195 and about200° C., or about 145 and about 195° C., or from about 150 and about195° C., or from about 155 and about 195° C., or from about 160 andabout 195° C., or from about 165 and about 195° C., or from about 170and about 195° C., or from about 175 and about 195° C., or from about180 and about 195° C., or from about 185 and about 195° C., or fromabout 190 and about 195° C., or about 145 and about 190° C., or fromabout 150 and about 190° C., or from about 155 and about 190° C., orfrom about 160 and about 190° C., or from about 165 and about 190° C.,or from about 170 and about 190° C., or from about 175 and about 190°C., or from about 180 and about 190° C., or from about 185 and about190° C., or about 145 and about 185° C., or from about 150 and about185° C., or from about 155 and about 185° C., or from about 160 andabout 185° C., or from about 165 and about 185° C., or from about 170and about 185° C., or from about 175 and about 185° C., or from about180 and about 185° C., or about 145 and about 180° C., or from about 150and about 180° C., or from about 155 and about 180° C., or from about160 and about 180° C., or from about 165 and about 180° C., or fromabout 170 and about 180° C., or from about 175 and about 180° C., orabout 145 and about 175° C., or from about 150 and about 175° C., orfrom about 155 and about 175° C., or from about 160 and about 175° C.,or from about 165 and about 175° C., or from about 170 and about 175°C., or about 145 and about 170° C., or from about 150 and about 170° C.,or from about 155 and about 170° C., or from about 160 and about 170°C., or from about 165 and about 170° C., or about 145 and about 165° C.,or from about 150 and about 165° C., or from about 155 and about 165°C., or from about 160 and about 165° C., or about 145 and about 160° C.,or from about 150 and about 160° C., or from about 155 and about 160°C., or about 145 and about 155° C., or from about 150 and about 155° C.,or about 145 and about 150° C., or 145° C., 150° C., 155° C., 160° C.,165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195° C., 200° C.,and preferably from about 150 to about 190° C.

In embodiments, the heating of the polyamide hot-melt resin granule maybe performed at from about 30 to about 95° C., or from about 35 to about95° C., or from about 40 to about 95° C., or from about 45 to about 95°C., or from about 50 to about 95° C., or from about 55 to about 95° C.,or from about 60 to about 95° C., or from about 65 to about 95° C., orfrom about 70 to about 95° C., or from about 75 to about 95° C., or fromabout 80 to about 95° C., or from about 85 to about 95° C., or fromabout 90 to about 95° C., or from about 30 to about 90° C., or fromabout 35 to about 90° C., or from about 40 to about 90° C., or fromabout 45 to about 90° C., or from about 50 to about 90° C., or fromabout 55 to about 90° C., or from about 60 to about 90° C., or fromabout 65 to about 90° C., or from about 70 to about 90° C., or fromabout 75 to about 90° C., or from about 80 to about 90° C., or fromabout 85 to about 90° C., or from about 30 to about 85° C., or fromabout 35 to about 85° C., or from about 40 to about 85° C., or fromabout 45 to about 85° C., or from about 50 to about 85° C., or fromabout 55 to about 85° C., or from about 60 to about 85° C., or fromabout 65 to about 85° C., or from about 70 to about 85° C., or fromabout 75 to about 85° C., or from about 80 to about 85° C., or fromabout 30 to about 80° C., or from about 35 to about 80° C., or fromabout 40 to about 80° C., or from about 45 to about 80° C., or fromabout 50 to about 80° C., or from about 55 to about 80° C., or fromabout 60 to about 80° C., or from about 65 to about 80° C., or fromabout 70 to about 80° C., or from about 75 to about 80° C., or fromabout 30 to about 75° C., or from about 35 to about 75° C., or fromabout 40 to about 75° C., or from about 45 to about 75° C., or fromabout 50 to about 75° C., or from about 55 to about 75° C., or fromabout 60 to about 75° C., or from about 65 to about 75° C., or fromabout 70 to about 75° C., or from about 30 to about 70° C., or fromabout 35 to about 70° C., or from about 40 to about 70° C., or fromabout 45 to about 70° C., or from about 50 to about 70° C., or fromabout 55 to about 70° C., or from about 60 to about 70° C., or fromabout 65 to about 70° C., or from about 30 to about 65° C., or fromabout 35 to about 65° C., or from about 40 to about 65° C., or fromabout 45 to about 65° C., or from about 50 to about 65° C., or fromabout 55 to about 65° C., or from about 60 to about 65° C., or fromabout 30 to about 60° C., or from about 35 to about 60° C., or fromabout 40 to about 60° C., or from about 45 to about 60° C., or fromabout 50 to about 60° C., or from about 55 to about 60° C., or fromabout 30 to about 55° C., or from about 35 to about 55° C., or fromabout 40 to about 55° C., or from about 45 to about 55° C., or fromabout 50 to about 55° C., or from about 30 to about 50° C., or fromabout 35 to about 50° C., or from about 40 to about 50° C., or fromabout 45 to about 50° C., or from about 30 to about 45° C., or fromabout 35 to about 45° C., or from about 40 to about 45° C., or fromabout 30 to about 40° C., or from about 35 to about 40° C., or fromabout 30 to about 35° C., or 30° C., 35° C., 40° C., 45° C., 50° C., 55°C., 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., 90° C. and 95° C.

Surprisingly, the inventors observed that the higher the content of acidresidual functional groups, the better the liquid-solution incorporationcapacity of the polyamide hot-melt resins.

According to a preferred embodiment, the [NH₂]/[COOH] molar ratio of theresidual functional groups is below 2, preferably below 1.

According to an embodiment, the acid residual functional group contentof the polyamide hot-melt resins exceeds 2 mg of KOH/g of resingranules.

According to an embodiment, the amine residual functional group contentof the polyamide hot-melt resins is below 5 mg of KOH/g of resingranules.

Advantageously, one of the means enabling the polyamide hot-melt resingranules to be heated is a thermostatically-controlled mixer whose wallis heated by an oil bath or by hot water or by hot water vapor. It isunderstood that the polyamide hot-melt resin granules can be heated byany other equivalent heating means known to a person skilled in the artso long as its characteristics enable the desired aim of the inventionto be achieved.

Advantageously, at the end of step b) of mixing the liquid solutioncontaining the active ingredient into the hot granules, the polyamidehot-melt resin granules are substantially dry due to the fact that allof the liquid is completely absorbed.

According to another embodiment of the invention, the selection of thepolyamide hot-melt resins can be performed specifically according to thetitration method defined above.

According to another embodiment, there is provided a third object of thepresent invention which is a molded item made from a plurality ofpolyamide hot-melt resin granules synthesized from dimerized fatty acidshaving 12 to 24 carbons and diamines having 2 to 14 carbons, thegranules being loaded with active ingredient, wherein the polyamidehot-melt resin granules have amine residual functional groups and acidresidual functional groups in a [NH₂]/[COOH] molar ratio below 5 and ina quantity of the active ingredient between 0.01 and 55%, or from about0.1 and 55%, or from about 1 and 55%, or from about 5 and 55%, or fromabout 10 and 55%, or from about 15 and 55%, or from about 20 and 55%, orfrom about 25 and 55%, or from about 30 and 55%, or from about 35 and55%, or from about 40 and 55%, or from about 45 and 55%, or from about50 and 55%, or from about 0.01 and about 50%, or from about 0.1 and 50%,or from about 1 and 50%, or from about 5 and 50%, or from about 10 and50%, or from about 15 and 50%, or from about 20 and 50%, or from about25 and 50%, or from about 30 and 50%, or from about 35 and 50%, or fromabout 40 and 50%, or from about 45 and 50%, or from about 0.01 and about45%, or from about 0.1 and 45%, or from about 1 and 45%, or from about 5and 45%, or from about 10 and 45%, or from about 15 and 45%, or fromabout 20 and 45%, or from about 25 and 45%, or from about 30 and 45%, orfrom about 35 and 45%, or from about 40 and 45%, or from about 0.01 andabout 40%, or from about 0.1 and 40%, or from about 1 and 40%, or fromabout 5 and 40%, or from about 10 and 40%, or from about 15 and 40%, orfrom about 20 and 40%, or from about 25 and 40%, or from about 30 and40%, or from about 35 and 40%, or from about 0.01 and about 35%, or fromabout 0.1 and 35%, or from about 1 and 35%, or from about 5 and 35%, orfrom about 10 and 35%, or from about 15 and 35%, or from about 20 and35%, or from about 25 and 35%, or from about 30 and 35%, or from about0.01 and about 30%, or from about 0.1 and 30%, or from about 1 and 30%,or from about 5 and 30%, or from about 10 and 30%, or from about 15 and30%, or from about 20 and 30%, or from about 25 and 30%, or from about0.01 and about 25%, or from about 0.1 and 25%, or from about 1 and 25%,or from about 5 and 25%, or from about 10 and 25%, or from about 15 and25%, or from about 20 and 25%, or from about 0.01 and about 20%, or fromabout 0.1 and 20%, or from about 1 and 20%, or from about 5 and 20%, orfrom about 10 and 20%, or from about 15 and 20%, or from about 0.01 andabout 15%, or from about 0.1 and 15%, or from about 1 and 15%, or fromabout 5 and 15%, or from about 10 and 15%, or from about 0.01 and about10%, or from about 0.1 and 10%, or from about 1 and 10%, or from about 5and 10%, or from about 0.01 and about 5%, or from about 0.1 and 5%, orfrom about 1 and 5%, or from about 0.01 and about 1%, or from about 0.1and 1%, or from about 0.01 and about 0.1%, or 0.01%, 0.1%, 1%, 5%, 10%,15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% by weight of their weight.Preferably, the resins incorporate an active ingredient in quantities ofbetween about 1 and about 50%, or between about 5 and about 50%, orbetween about 10 and about 45%, or between about 15 and about 45%, orbetween about 20 and about 45% by weight compared to the total weight ofthe molded item. The item may be molded by injection-molding,blow-molding, extrusion, hot-pressing or coating.

According to an embodiment, the acid residual functional group contentof the polyamide hot-melt resin exceeds 2 mg of KOH/g of resin granules,and the amine residual functional group content of the resins is below 5mg of KOH/g of resin granules.

According to another embodiment, the hardness of the molded item of thepresent invention may be from about 60 to about 95 Shore A, or fromabout 65 to about 95 Shore A, or from about 70 to about 95 Shore A, orfrom about 75 to about 95 Shore A, or from about 80 to about 95 Shore A,or from about 85 to about 95 Shore A, or from about 90 to about 95 ShoreA, or from about 60 to about 90 Shore A, or from about 65 to about 90Shore A, or from about 70 to about 90 Shore A, or from about 75 to about90 Shore A, or from about 80 to about 90 Shore A, or from about 85 toabout 90 Shore A, or from about 60 to about 85 Shore A, or from about 65to about 85 Shore A, or from about 70 to about 85 Shore A, or from about75 to about 85 Shore A, or from about 80 to about 85 Shore A, or fromabout 60 to about 80 Shore A, or from about 65 to about 80 Shore A, orfrom about 70 to about 80 Shore A, or from about 75 to about 80 Shore A,or from about 60 to about 75 Shore A, or from about 65 to about 75 ShoreA, or from about 70 to about 75 Shore A, or from about 60 to about 70Shore A, or from about 65 to about 70 Shore A, or from about 60 to about65 Shore A, or 60, 65, 70, 75, 80, 85, 90, or 95 Shore A.

The molded items according to the invention are specifically necklaces,bracelets, pads and patches. In another embodiment, the items may betextile materials coated with the granules loaded with activeingredients.

The active ingredient may be of natural origin or of synthetic origin.According to another embodiment, the active ingredient may havebiocidal, well-being, cosmetic, therapeutic, phyto sanitary effects orproperties or a mixture thereof.

According to an embodiment, the active ingredient may be a biocidechosen from an insecticide, an insect repellent, a microbicide (abactericide, a fungicide, a virucide). According to another embodiment,the active ingredient may be selected from an attractant, a pheromone, ahormone, a vitamin, a perfume, an essential oil, a drug, a plant extractor a mixture thereof.

According to another embodiment, there is provided a fourth object ofthe present invention, as the use of polyimide hot-melt resin granulesas defined above as a solid support incorporating between 0.01 and 55%,or from about 0.1 and 55%, or from about 1 and 55%, or from about 5 and55%, or from about 10 and 55%, or from about 15 and 55%, or from about20 and 55%, or from about 25 and 55%, or from about 30 and 55%, or fromabout 35 and 55%, or from about 40 and 55%, or from about 45 and 55%, orfrom about 50 and 55%, or from about 0.01 and about 50%, or from about0.1 and 50%, or from about 1 and 50%, or from about 5 and 50%, or fromabout 10 and 50%, or from about 15 and 50%, or from about 20 and 50%, orfrom about 25 and 50%, or from about 30 and 50%, or from about 35 and50%, or from about 40 and 50%, or from about 45 and 50%, or from about0.01 and about 45%, or from about 0.1 and 45%, or from about 1 and 45%,or from about 5 and 45%, or from about 10 and 45%, or from about 15 and45%, or from about 20 and 45%, or from about 25 and 45%, or from about30 and 45%, or from about 35 and 45%, or from about 40 and 45%, or fromabout 0.01 and about 40%, or from about 0.1 and 40%, or from about 1 and40%, or from about 5 and 40%, or from about 10 and 40%, or from about 15and 40%, or from about 20 and 40%, or from about 25 and 40%, or fromabout 30 and 40%, or from about 35 and 40%, or from about 0.01 and about35%, or from about 0.1 and 35%, or from about 1 and 35%, or from about 5and 35%, or from about 10 and 35%, or from about 15 and 35%, or fromabout 20 and 35%, or from about 25 and 35%, or from about 30 and 35%, orfrom about 0.01 and about 30%, or from about 0.1 and 30%, or from about1 and 30%, or from about 5 and 30%, or from about 10 and 30%, or fromabout 15 and 30%, or from about 20 and 30%, or from about 25 and 30%, orfrom about 0.01 and about 25%, or from about 0.1 and 25%, or from about1 and 25%, or from about 5 and 25%, or from about 10 and 25%, or fromabout 15 and 25%, or from about 20 and 25%, or from about 0.01 and about20%, or from about 0.1 and 20%, or from about 1 and 20%, or from about 5and 20%, or from about 10 and 20%, or from about 15 and 20%, or fromabout 0.01 and about 15%, or from about 0.1 and 15%, or from about 1 and15%, or from about 5 and 15%, or from about 10 and 15%, or from about0.01 and about 10%, or from about 0.1 and 10%, or from about 1 and 10%,or from about 5 and 10%, or from about 0.01 and about 5%, or from about0.1 and 5%, or from about 1 and 5%, or from about 0.01 and about 1%, orfrom about 0.1 and 1%, or from about 0.01 and about 0.1%, or 0.01%,0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% by weightof their weight. Preferably, the resins incorporate an active ingredientin quantities of between about 1 and about 50%, or between about 5 andabout 50%, or between about 10 and about 45%, or between about 15 andabout 45%, or between about 20 and about 45% by weight of a liquidsolution containing an active ingredient having biocide, well-being andcosmetic, therapeutic, and phytosanitary effects or a mixture thereof.

The main advantage of the present invention is the ability toincorporate a sufficient quantity of active ingredient in the polyamidehot-melt resin granules thus allowing the control of diffusion of theseactive ingredients in respect of quantity and duration. In addition, themolded item obtained from granules loaded with a significant quantity ofactive ingredient offers more useful reserve or reservoir capacity fornumerous applications and less sequestration of active ingredients.

The present invention will be more readily understood by referring tothe following examples which are given to illustrate the inventionrather than to limit its scope. Indeed, the method described in thepresent invention can perfectly well be applied to other granulometricforms of polyamide hot-melt resins, such as powders, blocks, etc.

EXAMPLE 1 Incorporation of Active Ingredient Formed by a Liquid Mixtureof Essential Oils and Geraniol in Polyamide Hot-Melt Resin (PAHMR)Granules According to the Invention

Before the step of incorporation of the active ingredient, a choice ofhot-melt polyamide resin granules meeting the inventive criteria of thepresent invention is made. For this, seven types of polyamide hot-meltresins are characterized with respect to their residual functional groupcontent (acid and amine) as well as their [NH₂]/[COOH] molar ratio andsoftening temperature.

Among the seven polyamide hot-melt resins, three are known by the tradename TECHNOMELT®, three Uni-Rez® and one BUHNEN®. These are in the formof substantially spherical granules whose average diameter is around 3to 4 mm. The results are set out in Table 1.

TABLE 1 Table summarizing the physico-chemical properties of differentpolyamide hot-melt resins granules. Maximum Maximum [NH2]/ amine contentacid content [COOH] (mg KOH/g (mg KOH/g molar PAHMR Trade Name ofgranules) of granules) ratio No 1 TECHNOMELT 3 10 0.3 PA 641 No 2TECHNOMELT 3 10 0.3 PA 633 No 3 TECHNOMELT 2 10 0.2 PA 6208 No 4 BUHNENC0874 1 9.9 0.1 No 5 UNI-REZ 2656 4.7 0.8 5.9 No 6 UNI-REZ 2653 5 0.5 10No 7 UNI-REZ 2678 10 0.8 12.5

The active ingredient consists of a liquid mixture of essential oils,namely essential oil of peppermint and essential oil of thymesupplemented by geraniol. This active ingredient, named “S1”, has aninsect repellent action.

In order to proceed with the incorporation of the above-mentioned liquidactive ingredient, the hot-melt polyamide resin granules referred to inTable 1 are placed in a mixer provided with an agitator, which isimmersed in a bath of hot oil so as to reach the optimum temperatureappropriate for the incorporation of the liquid. Then, the granules areagitated until incorporation temperature is reached. Lastly, the liquidis poured onto the hot granules, still under agitation, until it istotally incorporated.

The maximum capacity of each of the polyamide hot-melt resins toincorporate the liquid constituting the active ingredient has beenassessed. The results are set out in Table 2.

TABLE 2 Table summarizing the liquid incorporation capacity of thedifferent polyamide resins Incorporation Maximum rate of [NH2]/[COOH]PAHMR temperature (° C.) incorporation (%) molar ratio No 1 65 41 0.3No2 50 20 0.3 No3 65 31 0.2 No4 50 28 0.1 No5 30 5 5.9 No6 30 6 10 No730 8.8 12.5 No8 45 9.2 5.9

Note that it is possible to incorporate up to 41% by weight of thisliquid in polyamide hot-melt resin granules no 1, compared to a rate of8.8% by weight for polyamide hot-melt resin granules no 7. The polyamidehot-melt resin granules no 5 is the same as polyamide hot-melt resingranules no 8; the difference is their incorporation temperature 30° C.and 45° C. respectively. At 45° C., these resin granules become sticky.At this temperature, they are not suitable for molding injection forexample. Indeed, these sticky resin granules loaded with activeingredient are difficult, even impossible to shape.

For a better visualization of these observations, FIG. 1 shows theinfluence of the [NH₂/COOH] molar ratio of residual functional groups onthe capacity of a polyamide hot-melt resins according to the inventionto incorporate liquid.

Note that polyamide hot-melt resins no 1, 2, 3 and 4 whose [NH₂/COOH]molar ratios are below 2 have a maximum incorporation rate of at least20% by weight. By contrast, polyamide hot-melt resins no 5, 6 and 7 havea maximum liquid incorporation rate below 10% of their weight.

These results clearly show that a polyamide hot-melt resin whose[NH₂]/[COOH] molar ratio of residual functional groups is below 2 hasthe unexpected capacity to incorporate a liquid 2 to 4 times greaterthan that of a polyamide hot-melt resin for which this molar ratioexceeds 5.

EXAMPLE 2 Influence of the Softening Temperature of Polyamide Hot-MeltResin Granules According to the Invention on the Capacity to Incorporatea Liquid Containing an Active Ingredient

In order to confirm the results obtained in Example 1, the softeningtemperature of each of the polyamide hot-melt resins in Table 1 wasvaried. The liquid with active ingredients is identical to that ofExample 1. The results are shown in FIG. 2.

FIG. 2 shows that the capacity of the polyamide hot-melt resin granulesto incorporate a liquid is linked to its softening temperature. In fact,the maximum liquid incorporation rate increases with the softeningtemperature of the polyamide resin. Each of polyamide hot-melt resins no1, 2, 3 and 4 have softening temperatures of around about 170 to about180° C., about 150 to about 160° C., about 170 to about 180° C. andabout 150 to about 160° C. respectively, whereas polyamide hot-meltresins no 5, 6, and 7 have softening temperatures of around about 120 toabout 130° C., about 95 to about 105° C. and about 135 to about 150° C.respectively.

EXAMPLE 3 Influence of the Chemical Nature of the Lipophilic LiquidConstituting the Active Ingredient on the Incorporation Capacity of thePolyamide Hot-Melt Resin Granules According to the Invention

To check whether the chemical nature of the liquid that constitutes theactive ingredient has a significant impact on the incorporation capacityof the polyamide hot-melt resin granules, the inventors replaced theliquid “S1” of Example 1 with the “S2” consisting of a liquid mixture ofessential oil of wintergreen supplemented by geraniol, all beingdissolved in sweet almond oil. This active ingredient has a functionthat is both soothing for a human and animal subject and repellent toinsects. Comparative tests were conducted on polyamide hot-melt resingranules 1 and 5. The results are provided in Table 3.

TABLE 3 Influence of the chemical nature of “S1” constituting the activeingredient Maximum [NH₂]/[COOH] PAHMR incorporation rate (%) molar ratioNo 1 40 0.3 No 5 15 5.9

Note that polyamide hot-melt resin no 1 still has an incorporationcapacity almost 2 times greater than that of polyamide hot-melt resin no5 for this “S1”.

Following the line of reasoning described above, “S1” was replaced with“S2” formed by the liquid mixture of essential oil of cedar andessential oil of peppermint dissolved in sweet almond oil, the polyamideresins remaining the same. This active ingredient has a function that issoothing and refreshing for a human or animal subject. The results areprovided in Table 4.

TABLE 4 Influence of the chemical nature of “S2” constituting the activeingredient Maximum [NH₂]/[COOH] PAHMR incorporation rate (%) molar ratioNo 1 52 0.3 No 5 12 5.9

Note that the polyamide hot-melt resin granules no 1 have anincorporation capacity 5 times greater than that of polyamide hot-meltresin granules no 5 for this “S2”.

While preferred embodiments have been described above and illustrated inthe accompanying drawings, it will be evident to those skilled in theart that modifications may be made without departing from thisdisclosure. Such modifications are considered as possible variantscomprised in the scope of the disclosure.

The invention claimed is:
 1. A composition, comprising a polyamide hot-melt resin having a chemical structure consisting of dimerized fatty acids and diamines, the polyamide hot-melt resin being configured to diffuse a diffusible essential oil loaded therein by mixing the diffusible essential oil into a polyamide hot-melt resin granule heated at about 30° C. to about 95° C., to obtain the polyamide hot-melt resin loaded with the diffusible essential oil, wherein the dimerized fatty acids have 12 to 24 carbons and the diamines have 2 to 14 carbons, wherein amine residual functional groups and acid residual functional groups within the polyamide hot-melt resin have a [NH₂]/[COOH] molar ratio below 1, wherein the acid residual functional group content of the polyamide hot-melt resin exceeds 2 mg of KOH/g of polyamide hot-melt resin, and the amine residual functional group content of the polyamide hot-melt resin is below 5 mg of KOH/g of polyamide hot-melt resin; and wherein the polyamide hot-melt resin incorporates the diffusible essential oil in quantities from about 0.01% to about 55% by weight of weight of the polyamide hot-melt resin.
 2. The composition of claim 1, wherein the polyamide hot-melt resin incorporates the diffusible essential oil in quantities from about 1 to about 50%, or from about 5 to about 50%, or from about 10 to about 45%, or from about 15 to about 45%, or from about 20 to about 45% by weight of weight of the polyamide hot-melt resin.
 3. The composition of claim 1, wherein the softening temperature of the resins is from about 145° C. to about 200° C.
 4. The composition of claim 3, wherein the softening temperature of the resins is from about 150° C. to about 190° C.
 5. The composition of claim 1, wherein the fatty acids comprise a monocarboxylic, a dicarboxylic, or a multicarboxylic acid.
 6. The composition of claim 5, wherein the dimerized acid is obtained by a polymerization reaction between an unsaturated fatty acid selected from the group consisting of oleic acid, linoleic acid, a dry unsaturated fatty acid, a semi-dry unsaturated fatty acid, and a monoalcohol ester with a low molecular weight derived from the unsaturated fatty acids.
 7. The composition of claim 1, wherein diamines are chosen from the group consisting of ethylenediamine, triethylenediamine, tetraethylenediamine, hexamethylenediamine, p- or m-xylenediamine, 4,4′-methylene bis(cyclohexylamine), 2,2-bis(4-cyclohexylamine), polyetherdiamine, isophoronediamine, 1,2- 1,3-, 1,4-cyclohexanediamine, 1,4-bis(2′-aminoethyl)benzene, piperazine, 1,3-di-4-piperidylpropane, and dimerized amines having amine functions from the conversion of the carboxyl group of the above dimerized acids.
 8. The composition of claim 1, further comprising a diffusible active ingredients-chosen from an insecticide, an insect repellent, a microbicide, an attractant, a pheromone, a hormone, a vitamin, a perfume, a drug, a plant extract, or a mixture thereof.
 9. The composition of claim 8, wherein the insecticide and the insect repellent are selected from the group consisting of pyrethroids, pyrethrines, carbamates, formamidines, carboxylic esters, N,N-diethyl-3-methylbenzamide (DEET), phenylpyrazoles, organophosphorus compounds, organohalogen compounds, neonicotinoids, avermectines, ivermectine, abamectine, doramectine, spinosyns, essential oils, terpenes, alcohol derivatives of terpenes, ester derivatives of terpenes, aldehyde derivatives of terpenes, sesquiterpenes, alcohol derivatives of sesquiterpenes, ester derivatives of sesquiterpenes, aldehyde derivatives of sesquiterpenes.
 10. A molded item made from a plurality of granules of the composition of claim 1, the item having been molded by injection-molding, blow-molding, extrusion, hot-pressing or coating.
 11. The molded item according to claim 10, further comprising a diffusible active ingredients chosen from an insecticide, an insect repellent, a microbicide, an attractant, a pheromone, a hormone, a vitamin, a perfume, a drug, a plant extract, or a mixture thereof.
 12. The composition of claim 1, wherein the polyamide hot-melt resin incorporates the diffusible essential oil in quantities from about 10% to about 45% by weight of weight of the polyamide hot-melt resin.
 13. The composition of claim 1, wherein the diffusible essential oil is provided as a liquid solution.
 14. A molded item made from a composition comprising a plurality of granules of polyamide hot-melt resin synthesized from dimerized fatty acids having 12 to 24 carbons and diamines having 2 to 14 carbons, the plurality of granules of polyamide hot-melt resin being loaded with a diffusible essential oil, by mixing the diffusible essential oil into the plurality of polyamide hot-melt resin granules heated at about 30° C. to about 95° C., and configured to diffuse the diffusible essential oil, wherein the plurality of polyamide hot-melt resin granules have amine residual functional groups and acid residual functional groups in a [NH₂]/[COOH] molar ratio below 1, wherein the acid residual functional group content of the polyamide hot-melt resins exceeds 2 mg of KOH/g of resin granules, and the amine residual functional group content of the polyamide hot-melt resins is below 5 mg of KOH/g of resin granules, and wherein the polyamide hot-melt resin incorporates the diffusible essential oil in quantities from about 0.01 to about 55% by weight compared to the total weight of the molded item, the item having been molded by injection-molding, blow-molding, extrusion, hot-pressing or coating.
 15. The molded item according to claim 14, further comprising a diffusible active ingredient is-chosen from an insecticide, an insect repellent, a microbicide, an attractant, a pheromone, a hormone, a vitamin, a perfume, an essential oil, a drug, a plant extract, or a mixture thereof.
 16. The molded item of claim 14, wherein the polyamide hot-melt resin incorporates the diffusible essential oil in about 10% to about 45% by weight compared to the total weight of the molded item. 